#include <bits/stdc++.h>
using namespace std;

double H, S1, V, L, K, n;
int ans;

int main() {
    cin >> H >> S1 >> V >> L >> K >> n;
    for (double i = 0.0; i < n; i += 1.0) {
        if (S1 - V * sqrt((H) / 5) - 0.0001 < i and S1 - V * sqrt((H - K) / 5) + L + 0.0001 > i)
            ans++;
    }
    cout << ans;

}